A flat plate-like device under test such as a semiconductor integrated circuit is subjected to an electric test as to whether or not it is produced as per specification. This kind of electric test is conducted by using an electric connecting apparatus such as a probe card, a probe block, a probe unit or the like provided with a plurality of probes to be individually pressed against an electrode of the device under test. The electric connecting apparatus of this kind is used for electrically connecting the electrode of a device under test and a tester.
As probes for use in such an electric connecting apparatus, there are a needle type one produced from a conductive metal fine wire, a blade type one formed like a plate, and a probe element type one using a probe element which, forms a projected electrode in wiring formed on one face of an electrically insulated sheet (film).
The blade type probe includes a single plate type one produced from a conductive metal plate, and a lamination type one in which exposure and etching of a photoresist and plating its etched portion are made one or more times.
The probe of either type is supported in a cantilever-like manner on a support member such as a wiring plate with its needle point pressed against an electrode of a device under test. When the needle point is pressed against the electrode of the device under test, an over drive acts on the probe, which is curved by elastic deformation.
As one of the blade type probes, there is a Z-shaped one comprising: a first and a second arm portions extending in a second direction at an interval in a first direction; a first and a second connecting portions for connecting the first and second arm portions at their front end portions and base end portions; a needle point portion following one side in the first direction of the first connecting portion; and a mounting portion following the other side in the first direction of the second connecting portion (FIG. 1 of Japanese Patent Appln. Public Disclosure (KOKAI) No. 7-115110).
As another one of the blade type probes, there is one comprising: a first and a second arm portions extending in a second direction at an interval in a first direction; a connecting portion for connecting the first and second arm portions at their base end portions; a needle point portion following one side in the first direction of the front end portion of the first arm portion; and a mounting portion following the other side in the first direction of the front end portion of the second arm portion (FIG. 2 of Japanese Patent Appln. Public Disclosure (KOKAI) No. 2003-57264).
In each of the conventional probes, the mounting portion is attached to a proper support member and supported in a cantilever-like manner on the support member with its needle point pressed, in that state, against the electrode of the device under test. Thereby, the over drive acts on the probe, and the probe is curved by elastic deformation in the first and second arm portions.
In both these conventional probes, however, the first and second arm portions only extend in parallel to each other in the second direction which is diagonal to the first direction, so that, if an over drive amount is increased to greatly elastically deform the first and second arm portions, breaking occurs at least in one of the first and second arm portions.
Particularly, in case of a microprobe for an integrated circuit, the cross sectional areas of the first and second arm portions are remarkably small, so that a first and a second mechanical strengths are weak, and it is difficult to increase the over drive amount and elastically deform the first and second arm portions to a great extent.
Unless the over drive amount can be increased as mentioned above, pressing force (needle pressure) of the needle point against the electrode of the device under test cannot be increased, so that a good electrical connection between the electrode of the device under test and the needle point cannot be realized and the position of the needle point in the first direction should be coincided highly accurately. As a result, an accurate test cannot be expected.